United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-82-009 May 1982
Project Summary
Measurement of High-
Temperature High-Pressure
Processes—A Summary Report
L Cooper and M. Shackleton
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The major focus of this program
was on particulate sampling in
advanced coal conversion technolo-
gies. Work performed was to assess
and develop the technology required
to perform high-temperature high-
pressure particulate sampling. In
addition to the effort denoted to
development and testing of an HTHP
sampler for the EPA/Exxon Mini-
plant, experience was gained in
design aspects of HTHP sampling
equipment and testing procedures. A
background study and planning effort
was directed toward possible future
sampling efforts in a coal gasification
facility. A state-of-the-art review of
HTHP sampling was also performed.
As a means of documenting the mate-
rials collected, a bibliography of arti-
cles, reports, and books relating to
HTHP sampling was compiled.
Further, a mailing list of persons inter-
ested in this technology is included in
the final report.
This Project Summary was devel-
oped by EPA's Industrial Environmen-
tal Research Laboratory, Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Overview of the Problem
Sampling for particulate matter in
hostile environments is a technology
that is still in the early stages of devel-
opment. The need for these techniques.
however, is yet to be fully realized.
High-temperature or high-pressure
(HTHP) sampling is integral to the reso-
lution of environmental concerns
resulting from the development of
emerging energy conversion technolo-
gies. There are also potential applica-
tions for HTHP sampling in current
technologies, including those in the
petrochemical industry.
The major focus of this program was
on particulate sampling in advanced
coal conversion technologies. Those
technologies of particular interest were
pressurized fluidized-bed combustion
(PFBC) and coal gasification (CG).
Although CG received attention during
this program, far more effort was
devoted to PFBC.
At present it has become more and
more evident that the successful devel-
opment of a PFB combined-cycle power
system hinges on the ability to produce
a clean gas stream. The reasonsfor pro-
viding a clean gas stream are two-fold:
(1) from an environmental point of view,
low levels of particulate emissions must
be achieved so that limits set by the EPA
and state regulatory agencies can be
met; and (2) more importantly to the
power system developer, the hot gas
stream must be sufficiently free of par-
ticulate matter to allow for long turbine
life. In general, it cannot be conclusively
stated that meeting one criteria auto-
matically satisfies the other in all cases.
A lot depends on the required control
level of environmental emissions in a
given location and the particular design
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constraints of the turbine in question.
Nevertheless, this all points to the fact
that HTHP paniculate and gaseous
cleanup systems must be developed to
provide for high thermodynamic effi-
ciency (by cleaning at elevated temper-
atures and pressures) and long system
life (by maintaining low levels of erosive
and corrosive materials). The report
focuses predominately on those
aspects related to paniculate collection.
To develop cleanup systems to meet
environmental and turbine standards, it
is necessary to perform stream sam-
pling both upstream and downstream of
each cleanup stage. In so doing, the
removal efficiency of each stage can be
determined. The measurements must
be accurate and comprehensive. Not
only must total stream paniculate load-
ing be measured, but also particle size
distribution must be determined. It is
well known that the particle size distri-
bution strongly affects the erosion and
deposition of turbine components. In
addition, the chemical composition of
the paniculate is important from the
standpoint of corrosive reactions that
can occur within the cleanup system
and on turbine surfaces.
Hence, it is clear that the sampling
system must be accurate, reliable, and
allow for post-examination of the sam-
ple. The system should provide the cap-
ability to survey across the duct to
determine nonuniformities in panicu-
late concentrations and panicle size
stratification.
The system constraints defined above
all point to the selection of an extractive
sampling approach for the purpose of
developing advanced power systems. In
situ, laser/optical approaches to pani-
culate measurement are currently
under development. Most of these
methodologies are yet to be proven in
HTHP environments. Once they are
fully developed, they will be extremely
useful tools, but in many applications
their primary function will be for moni-
toring system upsets on an operational
power system. In addition, their opera-
tion is generally based on the principle
of optical light scattering to determine
an optical diameter. The more conven-
tional extractive approaches discussed
here collect and size paniculate matter
on the basis of panicle aerodynamic
diameters. This parameter directly
correlates to the operational function of
inertia! and non-inertial cleanup de-
vices (cyclones, barrierfilters, and gran-
ular beds) and the turbine itself.
The arguments delineated previously
for the selection of an extractive
approach to paniculate sampling.for the
development of PFBC power systems
can easily be extended to the develop-
ment of other coal conversion technolo-
gies currently under development such
as low-Btu gasification combined
power cycle and magnetohydrodynamic
(MHO) coal conversion technologies.
Summary of Work Performed
The purpose of work performed was
to assess and develop the technology
required to perform HTHP sampling.
Efforts were put forth in several direc-
tions. The major emphasis of this pro-
gram was on the development of HTHP
sampling hardware for coal energy con-
version technologies. Other activities
included the development of special
purpose sampling hardware for coke
oven sampling, a versatile probe for
sampling conventional/combustion
processes at EPA's Industrial Environ-
mental Research Laboratory, Research
Triangle Park, NC (IERL-RTP) experi-
mental facilities and the HT calibration
of series cyclone trains for the EPA
Source Assessment Sampling System
(SASS). The information in the report
concentrates on the findings of those
activities related to coal conversion
technologies.
The major portion of work performed
included the development of sampling
hardware and subsequent testing in a
PFBC test rig. These efforts were even-
tually brought to fruition at the Exxon
Miniplant in Linden, NJ, in March 1977.
Two test series were performed at duct
conditions at 9 atm and 1350°F.
Valuable experience was gained in
the design aspects of HTHP sampling
equipment and testing procedures.
These related to probe design, sampling
procedures, and data analysis. The
highlights of the information obtained
are explained in more detail in the full
report.
In addition to the emphasis placed on
PFBC sampling, a background study and
planning effort was directed toward
possible future sampling efforts in a CG
facility. A survey was performed to
identify likely test sites and determine
what sampling requirements and prob-
lem areas would be encountered. This,
in turn, led to a study of how best to
sample gas streams containing tar
vapors. Several methods were pro-
posed for separating and collecting
these tars from the solid paniculate
matter present. A design exercise led to
a proposed system for sampling in a CG
process stream.
Concurrent with the experimental
tasks performed at the Exxon Miniplant,
a state-of-the-art (SOA) review of the
HTHP technology was performed. The
activities carried out under this portion
of the program were also varied. They
included a study of practical techniques
for measuring stream variables such as
pressure, temperature, and velocity. A
comprehensive telephone survey was
carried out to determine the possible
future applications and requirements
for HTHP sampling. The survey included
special sampling problems that might'
be expected to occur in practice.
Other SOA review activities included
a detailed study of problems associated
with the selection of materials for HTHP
probes. Material problems occurring in
the reducing atmospheres found in CG
systems present a much more severe
problem than those associated with oxi-
dizing environments such as those in
FBC applications. Highly corrosive
gases, such as H2S, present at elevated
temperatures pose substantial prob-
lems to the HTHP probe designer in
selecting metals capable of withstand-
ing these exposures.
Finally, as a means of documenting
the materials collected, a bibliography
of articles, reports, and books relating to
HTHP sampling technology and
selected coal conversion technologies
was assembled and is contained a? an
appendix in the full report. In addition,
through the various contacts estab-
lished in the course of the project, a
mailing list of interested persons was
prepared. This mailing list is also an
appendix in the full report.
General Findings and
Recommendations
The major effort conducted was a
demonstration of the extractive HTHP
sampling approach at the Exxon Mini-
plant. Test conditions were 9 atm and
1350°F. The major findings of this por-
tion of the program are summarized
below.
The first of two test series demon-
strated that the PFBC test stream could
be successfully contained using a con-
centric tube sliding seal approach in
conjunction with a double gate valve
arrangement for sampler isolation
while not in use. (See Figure 1.) Proce-
dures for probe insertion, sampling, and
withdrawal were successfully demon-
strated during the different test runs.
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Probe Drive
Hydraulic Cylinder
Microswitches for
Transverse Control
Dowtherm Coolant
Systems and Controls
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«•
Dowtherm Coolant
Supply and Return
Housing
Sample Line
Control Console
Hydraulic
Supply System
Control Valve
and Operator
To
Vent
Figure 1. High-temperature, high-pressure (PFBC) sampling system.
Test gases were cooled using a Dow-
therm cooling system to a nominal
450°F, and conventional impactor and
filter designs were used. During the
demonstration tests, particulate sam-
ples were collected both on a series of
seven impactor plates (two runs) and
also on a thimble filter (one run).
Repeatability of test data using the two
impactor test runs was judged as good
to excellent. Particulate matter was col-
lected during the two impactor runs
over a size range of 0.3 to 30/urn. This
material was subsequently examined
photomicrographically and analyzed
chemically. Results of this analysis
yielded no unexpected results.
A second test series was conducted
to examine the possible occurrence of
alkali metal condensation during sam-
ple cool down prior to collection. The
sampling probe was reconfigured so
that the sample first passed through a
scalping cyclone and total filter combi-
nation at test stream conditions. Subse-
quently, the sample was cooled by the
Dowtherm cooling system followed by a
second total filter. If alkali metal con-
densation had occurred then it was
expected that the downstream filter
catch would show a larger alkali metal
content. Chemical analysis failed to
show any significant alkali metal con-
densation effects although these
limited results were by no means
conclusive.
The Exxon results demonstrated that
the methods developed and the results
produced were wholly satisfactory for
this application. Had the technology
been demonstrated at the time,
cyclones calibrated for HTHP operation
would have proven more versatile and
eliminated the need for cooling prior to
collection.
The experience of the Exxon sampling
program, especially with regard to hard-
ware development and the results of
the SOA survey, pointed to various con-
clusions regarding the universality of
future sampler designs. Owing to the
wide range of test stream conditions
(including temperature, pressure, gas
composition, particulate loading,
stream velocity, and duct diameter), the
impact upon standardization of design
is great. It was found that design
requirements tend to be nonstandard.
thus sampler designs require custom
design approaches in response to the
particular set of above mentioned
parameters.
These broad design requirements
inevitably lead to new engineering
problems and a consequential custom
engineered system. Based on expe-
rience gathered during this program,
the costs of engineering, designing, cal-
ibrating, and acceptance testing of
these systems are deemed to be very
high. As a result, the development costs
of one-of-a-kind systems are high with
subsequent cost reduction occurring on
duplicate systems if they are required.
Some new approaches to HTHP sam-
pling system design were identified.
Future systems can conceivably be built
at lowercostwith greater versatilityand
safety by using a "total enclosure"
design approach in which the traveling
probe is totally isolated, thus eliminat-
ing the need for sliding seals. It was
concluded that HTHP cyclones need to
be developed and tested as a means of
increasing the allowable sampling time
over that of impactors. Where a cooling
system may be required to condense
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water and acid constituents, a water
mist approach may prove simpler and
less subject to maintenance problems
than the Dowtherm system used at
Exxon.
In addition to these improvements,
new forefronts of research and develop-
ment were identified. The next chal-
lenging problem confronting HTHP
sampler developers is that of CG emis-
sions sampling. Problems such as sepa-
ration and collection of tars, selection of
probe materials compatible with corro-
sive reducing atmospheres, and explo-
sion hazards must be overcome. These
problems are not simple and will be
overcome only through diligent
research and development programs.
L Cooper and M. Shackletori are with Acurex Corporation, Energy and Environ-
mental Division, Mountain View, CA 94042.
William B. Kuykendal is the EPA Project Officer (see below).
The complete report, entitled "Measurement of High-Temperature High-
Pressure Processes—A Summary Report," {Order No. PB 82-196 932; Cost:
$13.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
U S GOVERNMENT PRINTING OFFICE, 1982 — 559-017/0737
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